A very fannish notion it might be, but I'd have liked to have seen a 'proper' crossover between TNG and DS9. Maybe as one of those epic sized two parters so that they could afford to employ more than one of DS9's cast to appear.

When the two series were airing simultaneously, I wished they had a done a two-parter like that, with the setup on TNG and the resolution on DS9. It could have included a scene establishing Worf's interest in the station, though at that point they probably weren't even considering it.